Defence of dissertation in the field of engineering physics, Maria Morits, M.Sc.

Surface engineering – a versatile tool for the fabrication of functional nanomaterials and tough nanocomposites

Maria Morits, M.Sc., will defend the dissertation "Surface Engineering of Nanomaterials for Biomimetic and Hybrid Applications" on 21 June 2018 at 12 noon at the Aalto University School of Science, lecture hall TU1, Maarintie 8, Espoo. The thesis is devoted to surface engineering of nanomaterials. It includes exploration of possibilities and limitations of grafting of well-defined polymer brushes from cellulose nanocrystals and preparation and characterization of bulk nacre-mimetic clay-polymer nanocomposites.

Surface engineering opens great opportunities both in the field of nanocomposites through enhancement of compatibility of their components and in the field of functional nanomaterials by development of various topographies and obtaining of new physical and chemical properties of nanoobjects.

Cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) are important classes of nanomaterials because of their abundance, eco-friendliness and excellent mechanical properties. Therefore, most attention in this thesis was paid to the grafting of well-defined polymer brushes from the surfaces of CNCs and CNFs and studying both opportunities and limitations of this approach. Surface engineering based on using of polymer brushes allows obtaining of 3D topographies or synthesis of uniform inorganic shell on the surfaces of CNCs which are of interest for the variety of applications.

In recent decades many attempts have been made to create nacre-mimetic composite materials due to exceptional mechanical properties of nacre. However, nacre-mimetic nanocomposites were limited to thin films, while study of fracture mechanics of materials requires bulk samples. This thesis filled this gap and considered preparation and characterization of bulk nacre-mimetic nanocomposites.

Opponent: Associate Professor Emily Cranston, McMaster University, Canada

Custos: Professor Olli Ikkala, Aalto University School of Science, Department of Applied Physics